Interpretive Summary: The phase-out of production and use of methyl bromide due to its designation as an ozone depleting substance has resulted in an intensive search to identify alternative chemicals and combinations of strategies as alternatives to fumigation with methyl bromide. It is imperative that all alternative strategies including reduced risk or lower risk chemical alternatives receive vigorous field testing to insure growers that reliable and consistent levels of pest control can be achieved. Two formulations of Plantpro (PP45 and PP20), a reduced risk iodophore, were tested for effects on tomato growth and incidence of root-knot nematodes. Three field trials were performed during two growing seasons in two Florida locations. In general, PP45 and PP20 did not differ from the untreated control with respect to plant growth, disease, or yield. Also, PP45 and PP20 treatments did not generally differ from each other with respect to these evaluations.

Technical Abstract:
Two formulations of a water-soluble, iodophore were evaluated as potential alternatives to methyl bromide soil fumigation by assessing their effects on growth, disease and yield of tomato. Three field trials evaluating Plantpro 45 and Plantpro 20EC were conducted in 2001 at two locations in central Florida. Application of Plantpro 45 and Plantpro 20EC was performed through two drip irrigation lines while methyl bromide was shank applied in the planting bed. Methyl bromide treated soil consistently produced plants with increased shoot length, shoot weight, and root weight early in the season, healthier root condition and lower gall ratings throughout the season, and significantly greater yields compared to both Plantpro formulations in two of three experiments. Both Plantpro formulations resulted in root-knot nematode populations in soil similar to the nontreated control soil in all studies. In fall experiments at both locations, plants in methyl bromide treated soil had significantly less galling at the end of the season than both Plantpro formulations.